DATABASE NORMALIZATION

Ehsan Hamzei

NORMALIZATION??

• In RDBs >> For Transactional Purpose >> We Need to minimum the redundancy• In Insert• In Update• In Deletion

• Result in:• Consistency• Performance

FIRST NORMAL FORM

• Each cell contains only a single value.• Each record is unique.• Identified by primary key

EXAMPLE?

Name SSN Address Postal code

Ehsan Hamzei

3920221621 N435 Test alley, Test St, Test Sq, Tehran, Iran

231233213

Ali Hashemi 3242342432 N2131 Work alley, Work St, Work Sq, Mashhad, Iran

324234234

Hassan Mohammadi

2342342344 N2332 Home alley, Home St, Home Sq, LA, USA

324124234

EXAMPLE?

Name SSN Address Postal code

Ehsan Hamzei

3920221621

N435 Test alley, Test St, Test Sq, Tehran, Iran

231233213

Ali Hashemi 3242342432

N2131 Work alley, Work St, Work Sq, Mashhad, Iran

324234234

Hassan Mohammadi

2342342344

N2332 Home alley, Home St, Home Sq, LA, USA

324124234

EXAMPLE?

• Violated !!!• First Name , Last Name• Address >> Building Number, Alley Name, Street Name,

Locality, City, Country

• PK: SSN

EXAMPLE?

• Normalized (First Normal Form)

FN LN SSN BN AN SN LN City Country

Postal code

Ehsan Hamzei 3920221621 N435 Test alley

Test St Test Sq Tehran Iran 231233213

Ali Hashemi 3242342432 N2131 Work alley

Work St Work Sq

Mashhad

Iran 324234234

Hassan Mohammadi

2342342344 N2332 Home alley

Home St Home Sq

LA USA 324124234

EXAMPLE(2)

• Another Example?????

EXAMPLE(2)

• First Normal:

SECOND NORMAL FORM

• Must be first normal!• All non-key fields depend on all

componentsof the primary key.• Guaranteed when primary key is a single

field.

EXAMPLE

• This example is normal in (2nd NF), Because of the single component key!!!!!

FN LN SSN BN AN SN LN City Country

Postal code

Ehsan Hamzei 3920221621 N435 Test alley

Test St Test Sq Tehran Iran 231233213

Ali Hashemi 3242342432 N2131 Work alley

Work St Work Sq

Mashhad

Iran 324234234

Hassan Mohammadi

2342342344 N2332 Home alley

Home St Home Sq

LA USA 324124234

EXAMPLE(2)

• First Normal:

EXAMPLE(2)

• Second Normal:

THIRD NORMAL FORM

•No non-key field depends upon another.• All non-key fields depend only on the

primary key.

EXAMPLE???

FN LN SSN BN AN SN LN City Country

Postal code

Ehsan Hamzei 3920221621 N435 Test alley

Test St Test Sq Tehran Iran 231233213

Ali Hashemi 3242342432 N2131 Work alley

Work St Work Sq

Mashhad

Iran 324234234

Hassan Mohammadi

2342342344 N2332 Home alley

Home St Home Sq

LA USA 324124234

EXAMPLE???

• Violated !!!

• Country & City & LN & SN & BN depend on Postal Code!!!

EXAMPLEFN LN SSN Postal CodeEhsan Hamzei 3920221621 231233213Ali Hashemi 3242342432 324234234Hassan Mohammadi 2342342344 324321234

Postal Code

BN AN SN LN City Country

231233213

N435 Test Alley

Test St Test Sq Tehran Iran

324234234

N2131 Work Allry

Work St Work Sq

Mashhad

Iran

324124234

N2332 Home Alley

Home St

Home Sq

LA USA

EXAMPLE(2)

• First Normal:

EXAMPLE(2)

• Second Normal:

EXAMPLE(2)

• Third Normal Form

SUMMARY

•All Non-Key Column must depend on PK, All Part of PK and Only on PK!!!!!!

REFERENCE

• Data-Base Design (Practical Database Design for Relational Database Management Systems)• Instructional Services at KU Libraries, The University of

Kansas

THANKS